The Japanese government is about to set 100 millisieverts as lifetime, cumulative acceptable radiation exposure standard, counting both internal and external radiation exposure, and this is on top of the average 1.5 millisievert/year natural radiation exposure.

Up till now, the acceptable radiation exposure has been 1 millisievert per year, in addition to the natural radiation exposure in Japan which is about 1.5 millisievert per year. There has been no standard for lifetime cumulative radiation exposure.

I read the following Asahi Shinbun article, translated it, and realized how utterly meaningless the whole exercise was. No one knows how much extra radiation that the Japanese (and the rest of the northern hemisphere) have gotten thanks to the broken reactors and spent fuel pools at Fukushima I Nuke Plant. In parts of Fukushima Prefecture, the cumulative air radiation level already exceeded 100 millisieverts.

And how many people, other than the nuke plant workers, have been tested with the whole body counters? Answer: not many. Reasons often cited are: background radiation too high in Fukushima for proper testing; there are not many whole body counters in Japan, 100 at most. Then, I read that a man from Iitate-mura in Fukushima demanded he be tested for radiation using the whole body counter. He finally got his wish several months after the start of the accident, and they refused to tell him the number. He still doesn’t know how much radiation he’s received.

So, my conclusion is that this new so-called standard or the article like Asahi that discusses the standard is to imprint the number in people’s mind: “100 millisieverts, 100 millisieverts, it’s safe up to that number.” Yes, they’ll also tell you it’s the lifetime cumulative number, but that doesn’t mean a thing when you don’t know how much of it you have had to spend already since March.

Soon, as Dr. Yamashita already said in a slip of a tongue, it will be safe up to 100 millisieverts per year.

The working group of the Food Safety Commission that has been considering the effect of radioactive materials on humans disclosed the plan of the secretariat that would say “The cancer-causing effect of radiation becomes only noticeable at and above 100 millisieverts of lifetime cumulative radiation.” The number includes not just the internal radiation from food but also external radiation exposure from the environment. It does not count the natural radiation exposure. Based on this secretariat’s plan the Commission will come up with its final plan and submit it to the Ministry of Health, Labor and Welfare next week. However, there are those at the Ministry who worry that it won’t be easy to create a new standard.

In response to the Fukushima I Nuke Plant accident, the Ministry of Health, Labor and Welfare set the provisional safety standards on March 17 to regulate the sale of food items contaminated with radioactive materials. Then, it asked the Commission to evaluate the effect of internal radiation exposure from food on human health, in order to scientifically justify the provisional safety standards.

The Commission at first tried to come up with the radiation limit from food only, and carefully studied various international research papers including the paper which became the basis for the ICRP recommendation. However, there were few papers that discussed the radiation from food separately from all the other radiation, and the Commission decided it was not possible to show the effect of radiation on health by separating internal and external exposures. Instead, the Commission will set the lifetime cumulative amount of radiation allowable, which includes external radiation exposure. It will exclude the natural radiation exposure from cosmic rays, etc., which is about 1.5 millisievert per year average in Japan.

In considering the lifetime cumulative radiation, if one is exposed to 20 millisieverts of radiation in a short time in an emergency, then it will be desirable if the radiation exposure is under 80 millisieverts for the rest of one’s life.

また、子どもや胎児については成人より影響を受けやすいという研究があり、事務局案では「留意が必要」としている。

There are studies that show children and fetuses are more susceptible to radiation exposure, and the secretariat’s plan calls for “an attention”.

ＩＣＲＰの考え方では「１００ミリシーベルトを浴びると、発がんリスクが０．５％上がる」とされる。

According to the ICRP, “The cancer risk goes up by 0.5% with 100 millisieverts exposure.”

As to deciding on a new standard that includes external exposure, one commissioner said “It should be done by other government organization like the Nuclear Safety Commission, but no one is doing it. So we have to do it.”

The current provisional safety standards for foods is for an emergency situation. A safety limit is decided per different nuclide (iodine, cesium, etc) so that and the combined total radiation exposure from food does not exceed 17 millisieverts per year.

Once the conclusion by the Food Safety Commission is submitted, then the Ministry of Health, Labor and Welfare will have to reconsider the safety limit per food. The person in charge of the process said, “We thought they would give us the number as annual radiation exposure limit. If it is going to be the lifetime cumulative radiation exposure limit, it may take a long time as we will have to consider different food intake amount for different age groups, from young to old.”

The government-funded researchers and scholars are already busy imprinting this number “100 millisieverts” in the minds of the populace. The reference to X-rays and CT-scans are back. No need to worry up till 100 millisieverts!

Now, does anyone know how much radiation that the residents in Fukushima, Tohoku or Kanto have gotten since March 11? No one does. Are all vegetables in the market tested? No. They only sample one item from one plot from one farm in one city, and if that passes the test the entire crop from the entire city is considered safe.

Radioactive beef? What radioactive beef? The government will buy the meat and burn it, satisfied? Schoolyards with radiation exceeding 1 microsieverts/hour? So? Don’t come complaining unless it’s above 3.6 microsieverts/hour. All our experts say there’s no danger below 100 millisieverts! If you are exposed to 20 millisieverts this year, well you will have 80 millisieverts for the rest of your life (we don’t know how long) to spend, so don’t worry.

One Response to “AND NOW: Japanese Government Sets 100 Millisieverts As New Lifetime Standard”

[…] here that five years of 20 mSv per year would equal 100 mSv lifetime exposure–the newly revised lifetime maximum set by Japan after the start of the Fukushima nuclear disaster. And some cities in northern Japan, […]